Utah Code § 54-3-24
The supervising law enforcement official having jurisdiction in a geographical area where hostages are held, who has probable cause to believe that the holder of one or more hostages is committing a crime, may order a previously designated telephone company security employee to arrange to cut, reroute or divert telephone lines that serve the area in which the hostages are being held, in an emergency, for the purpose of preventing telephone communications by the holder of the hostages with any person other than a peace officer or person authorized by a peace officer.
The serving telephone company within the geographical area of the law enforcement unit shall designate a telephone company security official and an alternate to provide all required assistance to law enforcement officials to carry out the purpose of this section. Good faith reliance on an order given by a supervising law enforcement official shall constitute a complete defense to any action brought for conduct allowed under this section.
Utah Code § 54-3-24